one sent to president obama was intercepted offsite. all of them postmarked april 8th. and all postmarked for memphis. what gave it away was the common signature. i am kevin curtis and i approve this message, at the end of the letters. the test on the first letter to wicker, had proved inconclusive. and the second one, as well. they're trying to figure out how potent this ricin was. and while it initially tested positive, the further tests by the fbi have been inconclusive. they ordered more as they continue to investigate. >> all right, tracie potts in washington. thanks so much for that. >>> after a rollercoaster day of reports on the investigation into the boston bombings, it appears authorities have pictures of their suspect. the front page of this morning's "boston globe" claims authorities have image of bombing suspect. we also know the identity of the third victim killed by those blasts. 23-year-old lindsay lu, a grad student from china, has been identified by boston university. 29-year-old crystal campbell and 8-year-old martin richard were injured. chris, good